Resource Restriction Systems and Methods

ABSTRACT

Resource restrictions are associated with a user identifier. A resource restriction agent receives operating system calls related for resources and provides resource request data to a resource agent. The resource agent determines whether the resource is restricted based on the resource request data and resource restriction data and generates access data based on the determination. The resource restriction agent grants or denies the system call based on the access data.

BACKGROUND

This disclosure relates to enforcing resource restrictions in anenvironment.

Users may often have associated resource restrictions on a computerdevice, such as a personal computer or other computing device. Typicallythese resource restrictions are associated with a user identifier. Forexample, a parent may limit the availability of applications, such as ane-mail client and web browser, on a home computer for a child byassociating resource restrictions with the child's user identifier. Whenthe child logs onto the computer with his or her user identifier, theweb browser and e-mail client is not available. Likewise, a workgroupadministrator may limit the availability of resources on a businesscomputer for certain employees. For example, a software developmentcompany may limit file sharing and/or access to particular developmenttools for employees according to the employees' user profiles.

Restrictions may be circumvented if the restriction is predicated onpreventing the generation of a system call for the resource. Thus if auser determines how to generate the system call for a restrictedresource, the user can have access to the resource. For example, abrowser application can be restricted for a user by a restrictionprogram that inhibits the generation of menu items, desktop icons anddock icons for launching the browser application. However, if the userclicks on a web address in an HTML enabled document in a word processingprogram, the word processing program can generate a system call tolaunch the browser application, thus circumventing the restriction.

SUMMARY

Disclosed herein are systems and methods for enforcing resourcerestrictions.

In one implementation, an execution call to an operating system for anapplication launch is received above a user level, and a determinationis likewise made above a user level as to whether launch restrictionsfor a user restrict the application launch. The execution call iscancelled if the launch restrictions for the user restrict theapplication launch.

In another implementation, a system includes a data store, a resourcerestriction service, and a resource agent. The data store stores datathat associates resource restrictions with a user identifier Theresource restriction service is configured to receive system callsrelated to resources and directed to an operating system, determineresource request data associated with the system call, and provide theresource request data to a resource agent. The resource agent isconfigured to access the data store and determine whether the resourceis restricted based on the resource request data provided by theresource restriction agent and generate access data based on thedetermination. The access data are provided to the resource restrictionservice, which in turn grants or denies the system call based on theaccess data.

These and the additional implementations described below facilitateenforcement of resource restrictions on a computer system.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a system for enforcing resourcerestrictions.

FIG. 2 is a block diagram of an example network environment in which thesystem of FIG. 1 can be implemented.

FIG. 3 is a flow diagram of an example process for enforcing resourcerestrictions.

FIG. 4 is a flow diagram of an example kernel selection process forenforcing resource restrictions.

FIG. 5 is a flow diagram of an example process for enforcing resourcerestrictions with a user-specific agent.

FIG. 6 is a flow diagram of an example process for enforcing resourcerestrictions with a user-independent agent.

FIG. 7 is a flow diagram of an example time-out process for enforcingresource restrictions.

FIG. 8 is a flow diagram of an example process for enforcing resourcerestrictions.

DETAILED DESCRIPTION

FIG. 1 is a block diagram of a system 100 for enforcing resourcerestrictions. The system 100 can be implemented in a computer or in acomputer network. A data store 102 stores data defining resourcerestrictions for one or more users. In one implementation, the resourcerestrictions are associated with users by user identifiers, such as auser login names, user profiles, or other user identifiers. The resourcerestrictions may relate to particular resources, such as an applicationlaunch, listening to a socket connection, file sharing, or some otherresource initiated by a system call.

An operating system 104 includes a resource restriction service 106. Theresource restriction service 106 may comprise code that provides asystem-level service for receiving system calls and processing thesystem call to determine whether the corresponding resources arerestricted. In one implementation, the resource restriction service 106may comprise code that loads during a system startup, such as a systemextension or boot program. In another implementation, the resourcerestriction service 106 may comprise code that loads only as required,such as a library that is linked to a profile of a user havingassociated restrictions, and which is executed only when that user islogged onto the computer.

The resource restriction service 106 is configured to receive systemcalls and determine the user identifier of a user 120 associated withthe system call. In one implementation, the user identifier isdetermined according to the current user session 122. Thus, the systemcall for a resource is associated with the user 120 by the user session122 regardless of whether the user 120 requests the resource or if aseparate process 124 requests the resource. An example separate process124 may include a program that requests a restricted resource, e.g., aword processing program that includes an HTML link for a restrictedbrowser, or an agent or process launched either intentionally orinadvertently by the user 120.

In one implementation, the resource restriction service 106 iscooperatively associated with a resource agent 108 that determineswhether to grant or deny the system call. Alternatively, both thesefunctions can be implemented in the resource restriction service 106.The resource restriction service 106 provides resource request data,such as the user identifier and/or a system call identifier, to theresource agent 108. The resource agent 108 is configured to access thedata store 102 and determine whether the requested resource isrestricted for the user 120 based on the resource request data. In oneimplementation, the resource agent 108 is configured to determine one orboth of the user identifier and system call identifier as necessary tomake the restriction determination. For example, if the resource requestdata includes only a user identifier, then the resource agent 108 can beconfigured. to determine a system call identifier. Likewise, if theresource request data includes only a system call identifier, then theresource agent 108 can be configured to determine the user identifier,In another implementation, the resource request data may only indicatethat a system call has been received, and the resource agent 108 can beconfigured to determine both the user identifier and the system callidentifier.

The resource agent 108 can be instantiated on a per-user basis. Inanother implementation, the resource agent 108 can be a backgroundprocess that operates independent of any user.

The resource agent 108 generates access data (e.g., a value) based onthe determination and provides the access data to the resourcerestriction service 106, which, in turn, grants or denies the systemcall accordingly. In one implementation, the access data may be alogical value, e.g., a logic 0 to deny the system call and a logic 1 togrant the system call.

Communication between the resource restriction service 106 and theresource agent 108 may be through a privileged socket, such as aroot-owned socket. For example, upon loading the resource restrictionservice 106, the resource restriction service 106 may register aroot-owned socket. The privileged socket ensures that user-levelprocesses cannot be inserted into the authorization process.

In one implementation, the resource agent 108 informs the resourcerestriction service 106 that system calls should be monitored forspecific user identifiers. The user identifiers are registered with theresource restriction service 106, and thereafter any system calls forthe registered user identifiers cause the resource restriction service106 to send a request for access data to the resource agent 108.

In another implementation, the resource restriction service 106comprises a launch restriction extension and the resource agent 108comprises a user agent. The launch restriction extension is configuredto intercept execution calls to a kernel for an application launch anddetermine resource request data associated with the execution call, andto provide the resource request data to a user agent. The user agent isconfigured to determine whether an application launch is restrictedbased on the resource request data provided by the launch restrictionagent and generate the launch data based on the determination. Thelaunch restriction extension, in turn, grants or denies the executioncall based on the launch data.

In another implementation, the resource agent 108 and the resourcerestriction service 106 are privileged processes. For example, theresource agent 108 and the resource restriction service 106 can beroot-owned processes to limit user access.

An authorization program 110 is configured to define resourcerestrictions for users and store the defined resource restrictions inthe data store 102. The authorization program 110 may be associated witha particular user 130, such as a parent or a workgroup administrator, sothat it may only be executed during the user session 130, or may bepassword protected by a password known only by the use 130. Theauthorization program 110 can thus operate at the user level.

FIG. 2 is a block diagram of an example network environment 200 in whichthe system of FIG. 1 can be implemented. The network environment 200includes a computer 202 having a processor 204, a random access memory206, and a data store 208.

In one implementation, the computer 202 can be a client computer, suchas a computer connected to a network in a home or an office. The system100 of FIG. 1 can be implemented on the computer 202 and enforcesresource restrictions on the computer 202. For example, if the network210 is the Internet, the system 100 can preclude access to e-mail clientsoftware and web browsers for particular users of the computer 202.

In one implementation, the computer 202 can be a server computer, suchas a server connected to a local area network. A system wide process,such as a network daemon, can be used to implement a resource agent 108and communicate with resource restriction services 106 on devices 212,222. and 232. The devices 212, 222, and 232 may include client computersor other computer devices, such as personal digital assistants, wirelesscommunication devices, or other devices that can have associated userrestrictions. The system of FIG. 1 can also be implemented in thenetwork environment by other schemes, such as instantiating a resourceagent 108 on each client computer 212, 222, and 232, and centrallylocating the user restrictions in the data store 208.

FIG. 3 is a flow diagram of an example process 300 for enforcingresource restrictions. Stage 302 defines resource restrictions for auser. In one implementation, resource restrictions can be associatedwith a user identifier.

Stage 304 receives a system call to an operating system for a resourcerequest. In one implementation, the resource restrictions can beapplication launch restrictions, and the system calls can be executioncalls for an application launch.

Stage 306 determines if the resource restrictions for the user restrictthe resource request. This determination is based on the resourcerestrictions defined in stage 302.

Stage 308 cancels the system call if the resource restrictions for theuser restrict the resource request.

FIG. 4 is a flow diagram of an example kernel selection process 320 forenforcing resource restrictions. The kernel selection process 320 isimplemented in response to a resource request. Stage 322 determines auser identifier associated with the resource request. The useridentifier can be determined, for example, based on the current usersession of a user logged onto a computer.

Stage 324 determines if there are restrictions associated with the useridentifier. If there are no restrictions associated with the useridentifier, then stage 326 grants the system call.

If there are restrictions associated with the user identifier, however,then stage 328 determines if a kernel process is to determine if thesystem call is for a resource that is restricted for the user. Anexample of such a kernel process is a process to determine a restrictionbased on a bundle identifier of a software program, and which can beimplemented in the resource restriction service 108. If a kernel processis to make such a determination, then stage 330 grants or cancels thesystem call based on the kernel determination.

If however, a kernel process is not to make such a determination, thenstage 332 sends the resource request data to a resource agent (e.g., theresource agent 108). The resource agent may implement addedfunctionality not readily available in the kernel or through anextension, such determining a hash, for example.

Stage 334 determines the access data based on the resource request data.For example, the resource agent 108 can access the resource restrictionsstored in the data store 102 and generate access data, such as a 1 or a0, based on the resource request data.

Stage 336 sends the access data (e.g., a data value) to the kernelprocess, and thereafter stage 330 grants or cancels the system callaccordingly.

FIG. 5 is a flow diagram of an example process 350 for enforcingresource restrictions with a user-specific agent. In thisimplementation, an agent is instantiated for each user. Stage 352registers a root-owned socket for communicating with a kernel process,such as a socket for the resource restriction service 106.

Stage 354 obtains or determines a user identifier at the user's login,and stage 356 determines if restrictions are associated with the useridentifier. If restrictions are not associated with the user identifier,then stage 358 grants all system calls.

If, however, restrictions are associated with the user identifier, thenstage 360 launches a resource agent (e.g., the resource agent 108) andestablishes communication with the kernel process using the root-ownedsocket. Thereafter, system calls are monitored in stage 362 and grantedor canceled by the kernel process and resource agent depending on theresource restrictions associated with the user identifier.

FIG. 6 is a flow diagram of an example process 380 for enforcingresource restrictions with a user-independent agent. In thisimplementation, one agent is instantiated for all users.

Stage 382 registers a root-owned socket for communicating with a kernelprocess, such as a socket for the resource restriction service 106.

Stage 384 launches a resource agent (e.g., the resource agent 108) andestablishes communication between the resource agent and a kernelprocess using the root-owned socket. The resource agent may be launchedduring a boot process or in response to a first user login.

Stage 386 provides the user identifiers having associated resourcerestrictions to the kernel process. Thereafter, stage 388 receives asystem call, and stage 390 determines if restrictions are associatedwith the user identifier for the system call. If restrictions are notassociated with the user identifier, then stage 392 grants the systemcall.

If however, restrictions are associated with the user identifier, stage394 provides resource request data to the resource agent 108. Processstages similar to stages 334 and 336 of FIG. 4 are thereafterimplemented to grant or deny the system call.

FIG. 7 is a flow diagram of an example time-out process 400 forenforcing resource restrictions. The time-out process 400 is an errorprocess that facilitates the processing of allowed system calls in theevent that communication between the operating system process and theresource agent (e.g., the resource agent 108) is terminated or in theevent that the resource agent crashes or is terminated by a userattempting to circumvent the resource restrictions.

Stage 402 sends the resource request data to the resource agent.Thereafter, stage 404 determines if access data are received from theresource agent before a time-out period. If the access data are receivedfrom the resource agent before a time-out period, then stage 406 grantsor cancels the system call according to resource restrictions associatedwith the user.

If the access data are not received from the resource agent before atime-out period, however, then stage 408 determines if the requestedresource is an allowed resource. Allowed resource can include resourcespre-selected by another user, such as a parent or a workgroup manager.Alternatively, allowed resources can include resources associated withparticular system functions.

If the resource is not an allowed resource, then the system call iscancelled in stage 410; otherwise, the system call is granted in stage412.

FIG. 8 is a flow diagram of an example process 430 for enforcingresource restrictions. The example process 430 can be implemented in aresource agent (e.g., the resource agent 108). The restrictions can beidentifier-based, path-based, or hash-based, or based on some otheridentification scheme. Identifier-based restrictions limit access to aresource based on a resource identifier, such as a non-unique or uniquenumber. Path-based restrictions limit access to a resource based on apath. Hash-based restrictions limit access to a resource based on a hashof a file associated with the resource.

Stage 432 receives the resource request data from a resource restrictionservice (e.g., the resource restriction service 106). Stage 434determines if the resource is subject to a resource identifier-basedrestriction. If so, the system call is cancelled in stage 436.

If the resource is not subject to a resource identifier-basedrestriction, then stage 438 determines if the resource is subject to apath-based restriction. If so, the system call is cancelled in stage436.

If the resource is not subject to a path-based restriction, then stage440 determines if the resource is subject to a hash-based restriction.If so, the system call is cancelled in stage 436; otherwise, the systemcall is granted in stage 442.

The apparatus, methods, flow diagrams, and structure block diagramsdescribed in this patent document may be implemented in computerprocessing systems including program code comprising programinstructions that are executable by the computer processing system.Other implementations may also be used. Additionally, the flow diagramsand structure block diagrams described in this patent document, whichdescribe particular methods and/or corresponding acts in support ofsteps and corresponding functions in support of disclosed structuralmeans, may also be utilized to implement corresponding softwarestructures and algorithms, and equivalents thereof.

This written description sets forth the best mode of the invention andprovides examples to describe the invention and to enable a person ofordinary skill in the art to make and use the invention. This writtendescription does not limit the invention to the precise terms set forth.Thus, while the invention has been described in detail with reference tothe examples set forth above, those of ordinary skill in the art mayeffect alterations, modifications and variations to the examples withoutdeparting from the scope of the invention.

1-30. (canceled)
 31. A method comprising: receiving an execution call toan operating system for launching an application, the execution callassociated with resource request data that identifies a user;intercepting the execution call using an operating system kernelservice; from the operating system kernel service, providing theresource request data to a resource agent; receiving launch data fromthe resource agent in response; and granting or denying the executioncall based on the launch data, wherein the resource agent is configuredto execute in a user space and perform operations comprising:determining whether the launching of the application is restricted forthe user based at least in part on the resource request data provided bythe operating system kernel service; and generating the launch databased on the determination.
 32. The method of claim 31, wherein theoperating system kernel service is configured to communicate with theresource agent via a kernel control socket.
 33. The method of claim 32,wherein the kernel control socket is a root-owned socket.
 34. The methodof claim 31 further comprising: determining if the launch data isreceived before expiration of a time period; and if the launch data isnot received before the expiration of the time period, only granting theexecution call if the application is an allowed application.
 35. Themethod of claim 34, wherein an allowed application is defined by anapplication path.
 36. The method of claim 31, wherein the resource agentdetermines whether the launching of the application is restricted isfurther based on one or more launch restrictions.
 37. The method ofclaim 36, wherein the launch restrictions are defined by at least one ofan application path and an application hash.
 38. The method of claim 31,wherein the resource agent includes a user agent that is specific to theuser.
 39. The method of claim 31, wherein the resource request datacomprises data identifying the execution call.
 40. The method of claim31, wherein the operating system kernel service includes a launchrestriction extension of an operating system kernel.
 41. Anon-transitory machine readable medium storing an operating systemkernel service for execution by at least one processing unit, theoperating system kernel service comprising sets of instructions for:receiving an execution call to an operating system for launching anapplication, the execution call associated with resource request datathat identifies a user; intercepting the execution call; providing theresource request data to a resource agent; receiving launch data fromthe resource agent in response; and granting or denying the executioncall based on the launch data, wherein the resource agent is configuredto execute in a user space and perform operations comprising:determining whether the launching of the application is restricted forthe user based at least in part on the resource request data provided bythe operating system kernel service; and generating the launch databased on the determination.
 42. The non-transitory machine readablemedium of claim 41, wherein the operating system kernel servicecommunicates with the resource agent via a kernel control socket. 43.The non-transitory machine readable medium of claim 41, wherein theoperating system kernel service further comprises sets of instructionsfor: determining if the launch data is received before expiration of atime period; and if the launch data is not received before theexpiration of the time period, only granting the execution call if theapplication is an allowed application.
 44. The non-transitory machinereadable medium of claim 43, wherein an allowed application is definedby an application path.
 45. The non-transitory machine readable mediumof claim 41, wherein the resource agent includes a user agent that isspecific to the user.
 46. An electronic device comprising: a set ofprocessing units for executing sets of instructions; and anon-transitory machine readable medium storing an operating systemkernel service for execution by at least one of the processing units,the operating system kernel service comprising sets of instructions for:receiving an execution call to an operating system for launching anapplication, the execution call associated with resource request datathat identifies a user; intercepting the execution call; providing theresource request data to a resource agent; receiving launch data fromthe resource agent in response; and granting or denying the executioncall based on the launch data, wherein the resource agent is configuredto execute in a user space and perform operations comprising:determining whether the launching of the application is restricted forthe user based at least in part on the resource request data provided bythe operating system kernel service; and generating the launch databased on the determination.
 47. The electronic device of claim 46,wherein the resource agent determines whether the launching of theapplication is restricted is further based on one or more launchrestrictions.
 48. The electronic device of claim 47, wherein the launchrestrictions are defined by at least one of an application path and anapplication hash.
 49. The electronic device of claim 46, wherein theresource request data comprises data identifying the execution call. 50.The electronic device of claim 46, wherein the operating system kernelservice includes a launch restriction extension of an operating systemkernel.